A common firearm ball type ammunition as opposed to shotgun ammunition comprises a metallic cartridge case containing a volume of propellant, with a primer fixed at one end of the case and a bullet or projectile releasably attached at the other end of the case. The performance of this type of ammunition is restricted by reason of the propellant being ignited at a point furthest from the bullet. The propellant, when ignited, deflagrates producing high volumes of gas. When the pressure of the gas has built to a sufficient level, it causes separation of the bullet from the cartridge case and propels the bullet along a barrel of an associated firearm. At this time, any remaining unburnt propellant is also expelled from the case into the barrel where its deflagration efficiency is greatly reduced due to the decrease in pressure because of the greater volume to which it is exposed. As a consequence, the potential propulsive force applied by the deflagrating propellant is also reduced. Moreover, a point is reached where regardless of the addition of further propellant to the case, very little gain in bullet velocity is achieved as a substantial proportion of the additional propellant is likely to burn outside of the barrel of the firearm on exit of the bullet and thus provide no useful thrust or velocity to the bullet.
A further problem with a conventional round is the extraction and ejection of the spent case after firing, particularly in automatic weapons. Such weapons require an extraction and ejection system to eject the spent cartridge. Indeed failure of the extraction and ejection mechanism is one of the main causes of automatic weapon stoppages and other malfunctions.
Throughout this specification, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or comprising is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.